| 摘要 |
<p>596,783. Asymmetrically-conducting resistances. STANDARD TELEPHONES & CABLES, Ltd. July 31, 1944, No. 14576. Convention date, July 13, 1943. [Class 37] Dry contact selenium rectifier elements are manufactured with a selenium layer which contains about 0.1 per 'cent thallium in the region of pressure contact in the final assembly to render that portion of the selenium layer insulating. For example, a layer 4 of selenium powder is applied to one surface of a metal base-plate 1 about a centrally disposed mask which, when removed, exposes a portion of the base-plate to which is applied through a mask covering the first selenium layer, a second selenium layer 6<1> containing thallium, which may overlap or be the same thickness as the first selenium layer 4. Both layers are then pressure and heat treated and sprayed with a counter-electrode alloy layer 8. The element is afterwards subjected to electro-forming. Specification 526,482 is referred to.</p> |
